In the present work we report the sol-gel synthesis of pure TiO2 and (TiO2)1−x(Fe2O3)x nanocomposites with different Fe2O3 contents (x = 0, 0.1, 0.5, and 1.0 for pure TiO2, Fe2O3 incorporated 0.1, 0.5, and pure Fe2O3 which are denoted as PT, 0.1F, 0.5F, and PF , respectively). The structural, morphological, optical, and surface texture of the prepared nanocomposites were characterized using various techniques. The structural studies confirm the strong influence of Fe2O3 contents on the crystallite sizes and dislocation values. The size of the crystallites was increased by the increase in Fe2O3 contents. The bandgap values elucidated from DRS analysis were decreased from 3.15 eV to 1.91 eV with increasing Fe2O3 contents. The N2-Physorption analysis has confirmed the mesoporous nature of the samples with a comparable specific surface area of 35 m2/g. The photoelectrochemical measurements (CV, CA and EIS) were performed to assess the photoelectric properties of the prepared materials. It was found that the PT samples have the highest catalytic activity and photocurrent response compared to other composites. The reduction in current density was as follows: 2.8, 1.65, 1.5 and 0.9 mA/cm2, while the photocurrent response was ca. 800, 450, 45, 35 µA/cm2 for PT, 0.1F, 0.5F and PF samples, respectively. The EIS results showed that the (TiO2)1−x(Fe2O3)x nanocomposites exhibit lower charge transfer resistance than pure titania and hematite samples.

No abstract

Metal chalcogenides have recently gained intensive attention due to their tunable bandgap energy, optoelectronic characteristics, and exceptional optical absorption. Because of the potential advantage of photodetectors, photovoltaic, holographic recording systems, and field-effect transistors, bismuth tri-sulfide (Bi2S3) crystals, in particular, have attracted a lot of focus in scientific research. In this study, the low-cost nebulizer spray technique was employed to synthesize the proposed Bi2S3:Sn thin films on glass substrates, varying the Sn doping concentrations in Bi2S3 films (from 1 to 3%). The crystallites of the orthorhombic-structured polycrystalline Bi2S3 films were all oriented in the same direction (130). According to the XRD spectra, preferred orientation and crystalline quality were improved by Sn doping concentrations up to 2%, but, above 2% of the Sn doping ratio, the structural properties were decreased. With increasing Sn-doping levels, the estimated direct band gap (Eg) of the Bi2S3:Sn films decreased, reaching a low value of 2.01 eV at 2% Sn and then rising. A field emission scanning electron microscope (FESEM) was applied to determine the size and shape of the grains in prepared Sn: Bi2S3 films.The 2% Sn-doped Bi2S3 thin film may be more appropriate for high-speed optoelectronic devices due to its high responsivity (1.24 AW-1), external quantum efficiency (40%), and detectivity properties (1.83×1010Jones). A potential mechanism for photodetector performance in the presence of air and UV radiation was also discussed in the present work for the proposed Sn: Bi2S3 thin films.

No abstract

We report co-doping effects of transition metal elements (Ni, Co) primarily on the opto-electronic properties of CuO thin films. CuO, CuO:Ni(1%), CuO:Co(1%) and CuO:Ni(1%):Co(1%) thin films were deposited via the sprays pyrolysis route. Structural studies revealed the monoclinic CuO structure for all films. For all the films scanning electron microscope (SEM) images showed a crack-free and homogeneous surface. Photoluminescence (PL) spectra of all the films exhibited four emission peaks at 415, 451, 477, and 521 nm wavelengths. The optical bandgap (Eg) values were around 2.12 eV, 2.18 eV, 2.05 eV and 1.84 eV for CuO, CuO:Ni(1%), CuO:Co(1%) and CuO:Ni(1%):Co(1%) thin films, respectively. CuO:Ni(1%):Co(1%) photo-device displayed a large responsivity (R) of 0.43 AW-1, external quantum efficiency (EQE) of 100% and detectivity (D*) of 9.55x109Jones. Hence, co-doping of transition metal elements would be one of the effective approaches for enhancing opto-electronic properties of metal oxide compounds.